%T A Comparison of Parallel Implementations of Flux Corrected Transport Codes
%A  Jing\-ming Jong,  G. S. Stiles
%E  J. Wexler
%B OUG\-11: Developing Transputer Applications
%X We present the results of comparing implementations of the
   Flux Corrected Transport (FCT) method on transputers and
   several other parallel and sequential machines. FCT is a
   finite difference scheme used to solve fluid dynamics
   problem which may involve steep gradients or shocks; it has
   proven useful for both one\- and two\-dimensional problems
   in plasma physics, atmospheric sciences, and detonation
   studies. The method vectorizes very well and hence runs
   quickly on supercomputers. Since the calculations at each
   point involve only a small number of neighbors, the method
   can also be efficiently implemented on multi\-processor
   systems. We have run one\- and two\-dimensional problems on
   Transputers and several other systems, including a VAX 8650,
   a SUN 4/280, a four\-processor Ardent Titan, an
   eight\-processor Alliant FX/8, and a four\-processor Silicon
   Graphics 240GTX. We shall also compare our results to those
   obtained by Gustafson (1988) on the NCube/ten.If, in the
   1\-d problem, we consider the speed of a single T800 to be
   1.0, the SUN 4/280 ranks at 3.8, the VAX 8650 at 4.0, 8
   TSOOs at 7.9, the Silicon Graphics 240GTX at 27.0, the FX/8
   at 56.9, and the Titan at 64.4. On the 1\-d problem, again
   taking one T800 to have a speed of 1.0, the SUN comes in at
   3.6, 16 NCube nodes at 4.0, the 8650 at 4.3, 8 TSOOs at 7.7,
   the Titan at 65.3, and the FX/8 at 101.4. The transputer
   ranks highest if we calculate the cost\-effectiveness of the
   various systems by dividing the relative speed by the
   approximate cost. If we assume the 8 TSOOs have a
   cost\-effectiveness of 1.0 on the 1\-d problem, the Titan is
   second at 0.52, followed by the 240GTX at 0.17, the FX/8 at
   0.094, the SUN at 0.081, and the VAX at 0.021.